- Email: [email protected]
Quantitative and qualitative measures of poststroke walking activity with inertial technologies
Abstracts / Annals of Physical and Rehabilitation Medicine 60S (2017) e39–e43
CO154
Study of walking parameters in patients with multiple sclerosis under fampridine: Contribution of accelerometers in the evaluation of the response to treatment Charles Xavier Bichon Institut régional de réadaptation, centre Louis-Pierquin, Nancy, France E-mail address: [email protected] Objective The aim of this study is to measure the changes induced by fampridine on the spatiotemporal parameters of walk in patients with multiple sclerosis, as well as balance, endurance, physical activity and quality of life. Material/patients and methods This is a prospective monocentric preliminary study. Different evaluations were done at D0 and D14 from initiation of fampridine treatment: timed 25 feet walk (T25FW) as usually evaluated, iWalk (instrumented 6 minute walk test), iSway (instrumented balanced test) and iTUG (instrumented ® timed up and go test). The instrumentation included APDM Mobility Lab sensors. Another ambulatory accelerometry evaluation was ® implemented with Actigraph sensors and quality of life was assessed with SEP-59 survey. Results Twelve patients were included. The results showed: decrease of T25FW (12.1 ± 6.2 s to 10.7 ± 4.9 s, P = 0.003), increase of walking perimeter (239.0 ± 92.2 m to 281.9 ± 130.8 m, P = 0.015), increase of cadence at iWalk (89.2 ± 9.7 steps/min to 98.1 ± 12.9, P = 0.03) and significant decrease of support time during halfturn. Other parameters tend to improve, such as double support time, stride length or ambulatory energy consumption. Intergroup comparisons did not find any significant difference, but some parameters appear to be more favorable in the responder group. Finally, SEP-59 finds significant improvements in most psychological dimensions, unlike physical dimensions. Discussion, conclusion Fampridine appears to induce changes on other aspects than velocity, which will have to be evaluated later with statistically more robust evaluations. Keywords Multiple sclerosis; Fampridine; Accelerometry; Walking parameters Disclosure of interest The author has not supplied his declaration of competing interest. http://dx.doi.org/10.1016/j.rehab.2017.07.179 CO155
Development of an embedded gait analysis system for brain damaged patients Tong Li 1,∗ , Gilbert Pradel 2 , Anthony Supiot 1 , Nicolas Roche 1 , Didier Pradon 1 1 U1179 End:icap UVSQ, Inserm CHU Raymond-Poincaré, AP–HP, médicine physique et réadaptation, Garches, France 2 U1179 End:icap UVSQ, Inserm CHU Raymond-Poincaré AP–HP, ENS de Cachan, Cachan, France ∗ Corresponding author. E-mail address: [email protected] (T. Li) Objective Optical motion analysis systems are widely used to evaluate the efficiency of treatment/rehabilitation for poststroke patients. These systems are only available in clinical settings due to their size/cost and need of complicate post processing. This paper presents the development of an embedded low cost and easy-touse system for gait analysis, which measures the joints angles and automatically detects foot-off (FO) and foot-contact (FC) events of stroke walking. Material/patients and methods The system uses 7 wireless inertial measurement unit (IMUs) to measure the body segments orienta-
e41
tions and 2 ultra-wideband (UWB) rangefinders placed near the heels for foot relative distance measurement. Data from sensors are synchronized and recorded in SD card at 70 Hz by controller (AtoutNovation, France). The locomotion of 14 stroke and 4 healthy subjects have been evaluated simultaneously with proposed system and a 3D motion analysis system. Eight gait records at a self-selected speed along 8 m walkway were performed by each subject. The joint angles in sagittal plane were calculated using orientations of segments. To avoid perturbation of external magnetic field (e.g. treadmill walking), the magnetometer was not used, therefore the system cannot calculate 3D joints values. Relative feet distance and foot angular velocity were used to determinate gait events. The joints angles in sagittal plane are segmented, normalized and averaged in gait cycle automatically based on detected gait events. Results The comparisons between proposed system and motion capture system showed a precision of 28.6 ± 28.3 ms for FC detection and 18.1 ± 18.0 for FO events. 98.9% of FC and 98.8% of FO events were automatically detected. The comparisons show a precision of 4.3 ± 2.9◦ for knee, 2.9 ± 2.8◦ for ankle and 4.8 ± 3.4◦ for hip. Correlation coefficient of all joint angles are higher than 0.97. Discussion, conclusion The proposed system constitutes a new low cost and wearable device allowing to assess stroke patient’s locomotion. Indeed, gait event detection accuracy is acceptable since the data are sampled each 14 ms. The joint angles have a high correlation coefficient and the differences between the 2 systems are limited. Its performance and easy use make it a good candidate for pathological gait analysis in ecological conditions. Keywords Inertial sensor; Gait analysis; Body sensor networks; Temporal parameter estimation Disclosure of interest The authors have not supplied their declaration of competing interest. http://dx.doi.org/10.1016/j.rehab.2017.07.180 CO156
Quantitative and qualitative measures of poststroke walking activity with inertial technologies Noémie Duclos 1,∗ , Larissa Aguiar Tavares 1 , Gerald Parent 2 , Rachid Aissaoui 2 , Sylvie Nadeau 1 , Cyril Duclos 1 1 École de réadaptation, faculté de médecine, université de Montréal, centre de recherche interdisciplinaire en réadaptation, Montréal, QC, Canada 2 École de technologie supérieure, université de Montréal, centre de recherche du centre hospitalier universitaire de Montréal, laboratoire de recherche en imagerie et orthopédie, Montréal, QC, Canada ∗ Corresponding author. E-mail address: [email protected] (N. Duclos) Objective Inertial technologies (activity monitors, inertial sensors) allow the evaluation of the number of steps and spatialtemporal parameters (STP) in daily life environments. However, activity monitors, generally worn at the hip, are not accurate for quantifying steps at slow walking speed (< 0.8 m/s). Moreover, current models behind inertial sensors measurements estimate STP supposing symmetry between limbs. The current use of these tools decreases the accuracy of outdoor walking assessment in individuals poststroke since they generally walk slowly and have an asymmetrical gait pattern. The aim of this study was to assess the accuracy of: (1) an activity monitor placed at the ankle to count the number of steps and (2) an algorithm developed to estimate asymmetric STP in individuals poststroke. Material/patients and methods Up to now, eight poststroke individuals who were independent walkers (with or without walking ® aid) were recruited. Study 1: an activity monitor (Fitbit One) placed at the non-paretic ankle (not at the hip as recommended) was tested during a walk in a commercial center. The number of steps measured was compared to the one measured by video
e42
Abstracts / Annals of Physical and Rehabilitation Medicine 60S (2017) e39–e43
recording. Study 2: four inertial sensors (OPAL, APDM inc.) were placed bilaterally at the ankle and thigh of the participants and used to assess a new algorithm developed to estimate the right and left STP independently. The estimated STP was compared to those mea® sured simultaneously by a GAITRite walking mat. For each study, the agreement between data provided by the tools was estimated using Altman-Bland charts. Results Among participants, the range of walking speed ® (0.4–1.2 m/s) and STP asymmetry was large. In study 1, the Fitbit One error for the number of steps was acceptable (0.14–4.60%), for participants walking faster than 0.4 m/s. In study 2, the stride times were precisely estimated but the support times were underestimated (−13 [6.2]%) and the oscillation times overestimated (+ 30.1 [11.3]%). Spatial parameter estimation was inconsistent. ® Discussion, conclusion Placing the Fitbit One at the non-paretic ankle is a suitable method for evaluating the amount of poststroke walking, except for very slow walkers. The algorithm for estimating STP from inertial sensors needs further work before being used in the community. Keywords Inertial; Gait; Number of steps; Spatiotemporal parameters; Poststroke; Community ambulation Disclosure of interest The authors have not supplied their declaration of competing interest. http://dx.doi.org/10.1016/j.rehab.2017.07.181 CO157
Assessment of the metrological qualities of the inertial FOX Hikob compared to the reference system for adaptive trigger functional electrical stimulation to correct dropfoot in poststroke hemiplegic patients Franc¸ois Feuvrier 1,∗ , Benoît Sijobert 2 , Christine Azevedo 2 , Arnaud Dupeyron 3 , Isabelle Laffont 4 , Jérôme Froger 5 1 CHU de Montpellier, Nîmes, département de médecine physique et de réadaptation, Montpellier, France 2 LIRMM université de Montpellier 2, INRIA, Montpellier, France 3 CHU Carémeau, département de médecine physique et de réadaptation, Nîmes, France 4 CHU Lapeyronie, département de médecine physique et de réadaptation, Montpellier, France 5 CHU du Grau-du-Roi, rééducation et réadaptation neurologique, Le Grau-du-Roi, France ∗ Corresponding author. E-mail address: [email protected] (F. Feuvrier) Objective Eighty percent of poststroke patients are temporarily unable to walk without help, often with a dropfoot during the midswing phase. Functional electrical stimulation (FES) induces compensation of dropfoot by preprogrammed fixed stimulation, however they are not more effective than mechanical ankle foot orthesis. FES has the advantage of being able to provoke a physiological muscular contraction and respect the articular amplitude. Our objective is to evaluate the metrological quality of the inertial sensors for movement reconstruction in comparison to the gold standard motion analysis. The aim is to improve the SEF using adaptive triggers for dorsiflexion, in hemiplegic poststroke patients. Material/patients and methods Adults with supratentorial ischaemic or hemorrhagic stroke, presenting a foot-drop, able to walk 10 metres without human help, with or without a walking stick were included from May 2016 to June 2017. Patients with ankle dorsiflexion < 0◦ in knee extension were excluded. Synchronous gait analysis was performed using the VICON© system, the GAITRITE© walkway system and Fox Hikob inertial measurement unit (IMU). The main outcome is the measurement error for the dorsiflexion angle at the heel strike and midswing phase.
Results Eleven patients included so far, 7 right sided hemiplegia, 8 male, mean age 56 years. To compare the IMU with the gold standard VICON, the measurement errors were estimated by Blant Altman analysis. Dorsiflexion angle measurements demonstrated a bias of 0.43◦ between the two techniques, with the limits of agreement [−13.46◦ ; + 14.32◦ ] during stance phases and a bias of 0.72◦ with agreement values [−16.19◦ ; + 17.64◦ ] during swing phases. Discussion, conclusion The data treatment algorithms from IMU seem to be effective in measuring ankle dorsiflexion with small biases between techniques. The limits of agreement are too wide from a clinical perspective, probably due to a small sample size, but are narrow enough to warrant further technological research. Analysis of the full sample size will provide further information on the limits of agreement. Keywords Stroke; Drop foot; Functional electrical stimulation; Motion analysis Disclosure of interest The authors have not supplied their declaration of competing interest. http://dx.doi.org/10.1016/j.rehab.2017.07.182 P077
Association between perceived walking impairment and real-life gait measures in patients with chronic pain of lower limbs Cyrille Burrus 1,∗ , Philippe Terrier 2 , Joane Le Carré 2 , Bertrand Léger 2 , Franc¸ois Luthi 1 1 Clinique romande de réadaptation, réadaptation de l’appareil locomoteur, Sion, Switzerland 2 Institut de recherche en réadaptation-réinsertion, Sion, Switzerland ∗ Corresponding author. E-mail address: [email protected] (C. Burrus) Objective The biopsychosocial model combines patient’s subjective perception of their condition with objective measures of their functional limitation. Objective outcomes measured through functional tests are limited temporally and spatially. Hence, they may not reflect real-life capacities of patients. We recently developed an embedded method aimed at characterizing free-gait patterns in patients with chronic pain of lower limbs. The objective is to explore the associations between those gait quality measures and subjective and objective classical clinical measures of walking abilities. Material/patients and methods Over one week, 66 chronic lower limb pain inpatients (CLLPP) wore a simple accelerometer ® (Actigraph ). Trunk accelerations were measured continuously at 50 Hz across waking hours. In the acceleration signals, one-minute walking bouts were detected specifically. From a preliminary validation study, two gait quality indexes were adopted because of their capacity to differentiate between CLLPP and healthy controls: (1) movement intensity, which is of proxy of walking speed; and (2) gait automaticity, which reflects the degree of cautiousness adopted by the patient while walking. The subjective evaluation by patients of how much their pain interferes with walking abilities (pain interference, PI) was obtained through the brief pain inventory (BPI-Interference subscale). The 6-minute walk test (6 MWT) was used as a clinical and punctual measure of walking ability. Results Using univariate regressions, significant negative correlations were found between pain interference and 6 MWT (R2 = 0.21) and between PI and gait automaticity (R2 = 0.15). Similarly, a multivariate model reveals significant association between PI and objective gait measures (R2 = 0.27). Discussion, conclusion The results show that patients reporting a higher PI with their walking ability are more likely to exhibit a poor 6 MWT performance and a more cautious gait (lower gait automaticity). In contrast, the absence of correlation between PI and movement intensity may evidence that patients reporting lower PI do not exhibit systematically a higher spontaneous walking speed.
CO154
Study of walking parameters in patients with multiple sclerosis under fampridine: Contribution of accelerometers in the evaluation of the response to treatment Charles Xavier Bichon Institut régional de réadaptation, centre Louis-Pierquin, Nancy, France E-mail address: [email protected] Objective The aim of this study is to measure the changes induced by fampridine on the spatiotemporal parameters of walk in patients with multiple sclerosis, as well as balance, endurance, physical activity and quality of life. Material/patients and methods This is a prospective monocentric preliminary study. Different evaluations were done at D0 and D14 from initiation of fampridine treatment: timed 25 feet walk (T25FW) as usually evaluated, iWalk (instrumented 6 minute walk test), iSway (instrumented balanced test) and iTUG (instrumented ® timed up and go test). The instrumentation included APDM Mobility Lab sensors. Another ambulatory accelerometry evaluation was ® implemented with Actigraph sensors and quality of life was assessed with SEP-59 survey. Results Twelve patients were included. The results showed: decrease of T25FW (12.1 ± 6.2 s to 10.7 ± 4.9 s, P = 0.003), increase of walking perimeter (239.0 ± 92.2 m to 281.9 ± 130.8 m, P = 0.015), increase of cadence at iWalk (89.2 ± 9.7 steps/min to 98.1 ± 12.9, P = 0.03) and significant decrease of support time during halfturn. Other parameters tend to improve, such as double support time, stride length or ambulatory energy consumption. Intergroup comparisons did not find any significant difference, but some parameters appear to be more favorable in the responder group. Finally, SEP-59 finds significant improvements in most psychological dimensions, unlike physical dimensions. Discussion, conclusion Fampridine appears to induce changes on other aspects than velocity, which will have to be evaluated later with statistically more robust evaluations. Keywords Multiple sclerosis; Fampridine; Accelerometry; Walking parameters Disclosure of interest The author has not supplied his declaration of competing interest. http://dx.doi.org/10.1016/j.rehab.2017.07.179 CO155
Development of an embedded gait analysis system for brain damaged patients Tong Li 1,∗ , Gilbert Pradel 2 , Anthony Supiot 1 , Nicolas Roche 1 , Didier Pradon 1 1 U1179 End:icap UVSQ, Inserm CHU Raymond-Poincaré, AP–HP, médicine physique et réadaptation, Garches, France 2 U1179 End:icap UVSQ, Inserm CHU Raymond-Poincaré AP–HP, ENS de Cachan, Cachan, France ∗ Corresponding author. E-mail address: [email protected] (T. Li) Objective Optical motion analysis systems are widely used to evaluate the efficiency of treatment/rehabilitation for poststroke patients. These systems are only available in clinical settings due to their size/cost and need of complicate post processing. This paper presents the development of an embedded low cost and easy-touse system for gait analysis, which measures the joints angles and automatically detects foot-off (FO) and foot-contact (FC) events of stroke walking. Material/patients and methods The system uses 7 wireless inertial measurement unit (IMUs) to measure the body segments orienta-
e41
tions and 2 ultra-wideband (UWB) rangefinders placed near the heels for foot relative distance measurement. Data from sensors are synchronized and recorded in SD card at 70 Hz by controller (AtoutNovation, France). The locomotion of 14 stroke and 4 healthy subjects have been evaluated simultaneously with proposed system and a 3D motion analysis system. Eight gait records at a self-selected speed along 8 m walkway were performed by each subject. The joint angles in sagittal plane were calculated using orientations of segments. To avoid perturbation of external magnetic field (e.g. treadmill walking), the magnetometer was not used, therefore the system cannot calculate 3D joints values. Relative feet distance and foot angular velocity were used to determinate gait events. The joints angles in sagittal plane are segmented, normalized and averaged in gait cycle automatically based on detected gait events. Results The comparisons between proposed system and motion capture system showed a precision of 28.6 ± 28.3 ms for FC detection and 18.1 ± 18.0 for FO events. 98.9% of FC and 98.8% of FO events were automatically detected. The comparisons show a precision of 4.3 ± 2.9◦ for knee, 2.9 ± 2.8◦ for ankle and 4.8 ± 3.4◦ for hip. Correlation coefficient of all joint angles are higher than 0.97. Discussion, conclusion The proposed system constitutes a new low cost and wearable device allowing to assess stroke patient’s locomotion. Indeed, gait event detection accuracy is acceptable since the data are sampled each 14 ms. The joint angles have a high correlation coefficient and the differences between the 2 systems are limited. Its performance and easy use make it a good candidate for pathological gait analysis in ecological conditions. Keywords Inertial sensor; Gait analysis; Body sensor networks; Temporal parameter estimation Disclosure of interest The authors have not supplied their declaration of competing interest. http://dx.doi.org/10.1016/j.rehab.2017.07.180 CO156
Quantitative and qualitative measures of poststroke walking activity with inertial technologies Noémie Duclos 1,∗ , Larissa Aguiar Tavares 1 , Gerald Parent 2 , Rachid Aissaoui 2 , Sylvie Nadeau 1 , Cyril Duclos 1 1 École de réadaptation, faculté de médecine, université de Montréal, centre de recherche interdisciplinaire en réadaptation, Montréal, QC, Canada 2 École de technologie supérieure, université de Montréal, centre de recherche du centre hospitalier universitaire de Montréal, laboratoire de recherche en imagerie et orthopédie, Montréal, QC, Canada ∗ Corresponding author. E-mail address: [email protected] (N. Duclos) Objective Inertial technologies (activity monitors, inertial sensors) allow the evaluation of the number of steps and spatialtemporal parameters (STP) in daily life environments. However, activity monitors, generally worn at the hip, are not accurate for quantifying steps at slow walking speed (< 0.8 m/s). Moreover, current models behind inertial sensors measurements estimate STP supposing symmetry between limbs. The current use of these tools decreases the accuracy of outdoor walking assessment in individuals poststroke since they generally walk slowly and have an asymmetrical gait pattern. The aim of this study was to assess the accuracy of: (1) an activity monitor placed at the ankle to count the number of steps and (2) an algorithm developed to estimate asymmetric STP in individuals poststroke. Material/patients and methods Up to now, eight poststroke individuals who were independent walkers (with or without walking ® aid) were recruited. Study 1: an activity monitor (Fitbit One) placed at the non-paretic ankle (not at the hip as recommended) was tested during a walk in a commercial center. The number of steps measured was compared to the one measured by video
e42
Abstracts / Annals of Physical and Rehabilitation Medicine 60S (2017) e39–e43
recording. Study 2: four inertial sensors (OPAL, APDM inc.) were placed bilaterally at the ankle and thigh of the participants and used to assess a new algorithm developed to estimate the right and left STP independently. The estimated STP was compared to those mea® sured simultaneously by a GAITRite walking mat. For each study, the agreement between data provided by the tools was estimated using Altman-Bland charts. Results Among participants, the range of walking speed ® (0.4–1.2 m/s) and STP asymmetry was large. In study 1, the Fitbit One error for the number of steps was acceptable (0.14–4.60%), for participants walking faster than 0.4 m/s. In study 2, the stride times were precisely estimated but the support times were underestimated (−13 [6.2]%) and the oscillation times overestimated (+ 30.1 [11.3]%). Spatial parameter estimation was inconsistent. ® Discussion, conclusion Placing the Fitbit One at the non-paretic ankle is a suitable method for evaluating the amount of poststroke walking, except for very slow walkers. The algorithm for estimating STP from inertial sensors needs further work before being used in the community. Keywords Inertial; Gait; Number of steps; Spatiotemporal parameters; Poststroke; Community ambulation Disclosure of interest The authors have not supplied their declaration of competing interest. http://dx.doi.org/10.1016/j.rehab.2017.07.181 CO157
Assessment of the metrological qualities of the inertial FOX Hikob compared to the reference system for adaptive trigger functional electrical stimulation to correct dropfoot in poststroke hemiplegic patients Franc¸ois Feuvrier 1,∗ , Benoît Sijobert 2 , Christine Azevedo 2 , Arnaud Dupeyron 3 , Isabelle Laffont 4 , Jérôme Froger 5 1 CHU de Montpellier, Nîmes, département de médecine physique et de réadaptation, Montpellier, France 2 LIRMM université de Montpellier 2, INRIA, Montpellier, France 3 CHU Carémeau, département de médecine physique et de réadaptation, Nîmes, France 4 CHU Lapeyronie, département de médecine physique et de réadaptation, Montpellier, France 5 CHU du Grau-du-Roi, rééducation et réadaptation neurologique, Le Grau-du-Roi, France ∗ Corresponding author. E-mail address: [email protected] (F. Feuvrier) Objective Eighty percent of poststroke patients are temporarily unable to walk without help, often with a dropfoot during the midswing phase. Functional electrical stimulation (FES) induces compensation of dropfoot by preprogrammed fixed stimulation, however they are not more effective than mechanical ankle foot orthesis. FES has the advantage of being able to provoke a physiological muscular contraction and respect the articular amplitude. Our objective is to evaluate the metrological quality of the inertial sensors for movement reconstruction in comparison to the gold standard motion analysis. The aim is to improve the SEF using adaptive triggers for dorsiflexion, in hemiplegic poststroke patients. Material/patients and methods Adults with supratentorial ischaemic or hemorrhagic stroke, presenting a foot-drop, able to walk 10 metres without human help, with or without a walking stick were included from May 2016 to June 2017. Patients with ankle dorsiflexion < 0◦ in knee extension were excluded. Synchronous gait analysis was performed using the VICON© system, the GAITRITE© walkway system and Fox Hikob inertial measurement unit (IMU). The main outcome is the measurement error for the dorsiflexion angle at the heel strike and midswing phase.
Results Eleven patients included so far, 7 right sided hemiplegia, 8 male, mean age 56 years. To compare the IMU with the gold standard VICON, the measurement errors were estimated by Blant Altman analysis. Dorsiflexion angle measurements demonstrated a bias of 0.43◦ between the two techniques, with the limits of agreement [−13.46◦ ; + 14.32◦ ] during stance phases and a bias of 0.72◦ with agreement values [−16.19◦ ; + 17.64◦ ] during swing phases. Discussion, conclusion The data treatment algorithms from IMU seem to be effective in measuring ankle dorsiflexion with small biases between techniques. The limits of agreement are too wide from a clinical perspective, probably due to a small sample size, but are narrow enough to warrant further technological research. Analysis of the full sample size will provide further information on the limits of agreement. Keywords Stroke; Drop foot; Functional electrical stimulation; Motion analysis Disclosure of interest The authors have not supplied their declaration of competing interest. http://dx.doi.org/10.1016/j.rehab.2017.07.182 P077
Association between perceived walking impairment and real-life gait measures in patients with chronic pain of lower limbs Cyrille Burrus 1,∗ , Philippe Terrier 2 , Joane Le Carré 2 , Bertrand Léger 2 , Franc¸ois Luthi 1 1 Clinique romande de réadaptation, réadaptation de l’appareil locomoteur, Sion, Switzerland 2 Institut de recherche en réadaptation-réinsertion, Sion, Switzerland ∗ Corresponding author. E-mail address: [email protected] (C. Burrus) Objective The biopsychosocial model combines patient’s subjective perception of their condition with objective measures of their functional limitation. Objective outcomes measured through functional tests are limited temporally and spatially. Hence, they may not reflect real-life capacities of patients. We recently developed an embedded method aimed at characterizing free-gait patterns in patients with chronic pain of lower limbs. The objective is to explore the associations between those gait quality measures and subjective and objective classical clinical measures of walking abilities. Material/patients and methods Over one week, 66 chronic lower limb pain inpatients (CLLPP) wore a simple accelerometer ® (Actigraph ). Trunk accelerations were measured continuously at 50 Hz across waking hours. In the acceleration signals, one-minute walking bouts were detected specifically. From a preliminary validation study, two gait quality indexes were adopted because of their capacity to differentiate between CLLPP and healthy controls: (1) movement intensity, which is of proxy of walking speed; and (2) gait automaticity, which reflects the degree of cautiousness adopted by the patient while walking. The subjective evaluation by patients of how much their pain interferes with walking abilities (pain interference, PI) was obtained through the brief pain inventory (BPI-Interference subscale). The 6-minute walk test (6 MWT) was used as a clinical and punctual measure of walking ability. Results Using univariate regressions, significant negative correlations were found between pain interference and 6 MWT (R2 = 0.21) and between PI and gait automaticity (R2 = 0.15). Similarly, a multivariate model reveals significant association between PI and objective gait measures (R2 = 0.27). Discussion, conclusion The results show that patients reporting a higher PI with their walking ability are more likely to exhibit a poor 6 MWT performance and a more cautious gait (lower gait automaticity). In contrast, the absence of correlation between PI and movement intensity may evidence that patients reporting lower PI do not exhibit systematically a higher spontaneous walking speed.